Science / Weather / Hydrosphere: Considered as the water portion of the earth's surface. Part of the geosphere.
Science / Weather / Geosphere: Considered the solid portions of the earth, including the hydrosphere and the lithosphere, as opposed to the atmosphere, which lies above it. At their conjunction is the biosphere. MORE
Science / Biology / Gaia: A hypothetical superorganism composed of the Earths four spheres: the biosphere, hydrosphere, lithosphere, and atmosphere. MORE